Four-wave frequency mixing in dye vapor

An experimental investigation was made of four-wave frequency mixing of YAG laser radiation in paraterphenyl vapor under two-photon resonance conditions. An experimental estimate was made of the nonlinear susceptibility χ⁽³⁾≈10^–31 cgs esu. This value is comparable with the quasiresonant susceptibilities of alkali metal atoms and is considerably greater than the resonant susceptibilities χ⁽³⁾ of the simplest molecules of the NO and CO types. The present paper is the first on nonlinear mixing of radiation frequencies in dye vapors.